In batch .drc script, klayout version prior to 0.27.12, writing OASIS file, how to enable CBLOCKs in OASIS-writer-options (ala SaveLayoutOptions)?

[sto6]

As of 0.27.12 (I test against 0.27.4 & 0.29.2), CBLOCKS are enabled by default in OASIS writer. For older klayout versions, in .rb batch script I'm able to use SaveLayoutOptions to enable CBLOCKS before writing an OASIS file. How to do the same/similar (if possible) in a .drc script (where to give an altered SaveLayoutOptions)?

For example using ol parameter (klayout -b -r xor.drc ... -rd ol=xor.oas) with the script towards end of (fall 2014): https://www.klayout.de/forum/discussion/100/xor-vs-diff-tool which has line: $ol && target($ol, $co || "XOR")

aside: That script has issues with OASIS named layers: A layerInfo.to_s is used as hash-key, and also as .input() parameter. It can yield format "met3 (46/0)" which is not supported by .input(), and such hash-keys for same layer/datatype pair can differ between the a/b input layout-files (if either or both are OASIS format). Thank you.